As an example of a metal-resin composite body, FIG. 8 shows a case 1 with a connector 11 used for housing a wiring board (hereinafter referred to as a case with a connector or simply a case) in which the connector 11 that is a resin structure is integrated with a case main body 2 (also referred to as a case main body) used for housing a wiring board. The case main body 2 is a metal component and assumes a rectangular parallelepiped tray shape. The connector 11 is integrated with an opening portion 7 of a side wall 5 (simply referred to as a wall 5) formed around a bottom wall (bottom plate) 3 of the case main body 2. FIG. 8 is a general structural perspective view of the case 1. FIG. 9 is a sectional view of the case 1. In the case 1, the connector 11 is formed so as to project both inner and outer sides of the side wall 5. As shown in FIG. 9, the connector 11 includes a part of a terminal fitting 21, and each end 21a, 21b of the terminal fitting 21 projects (exposed) inward and outward of the case main body 2. In addition, the end 21b of the terminal fitting 21 is connected to a wiring board 31 to be accommodated in the case 1.
The case 1 that is the metal-resin composite body is formed by injection molding where, for example, the case main body 2 and the terminal fitting 21 are positioned (disposed) in a mold as insert articles, and resin is filled in a cavity (space) corresponding to the connector 11 (See Japanese Patent Application Laid-Open (kokai) No. H10-74560). FIGS. 8 and 9 show the case 1 with the connector 11 integrated with only one opening portion 7 (simply called as an opening) on the left hand side in the drawing. The opening 7 assumes a “U”-shaped notch that cuts into an upper end (an end opposed to a substrate) of the side wall 5.
In such case 1, a space “G” (gap) is formed between the “U”-shaped inner end (also referred to as a projecting portion) 21b, which projects inward of the case 1, of the terminal fitting 21 and the bottom wall 3 of the case main body 2. On the other hand, a portion of the connector 11 which projects outward of the case 1 has a recessed portion 16 where the outer end 21a of the terminal fitting 21 is exposed therein.
In the case 1 having the connector, the case main body 2 and the terminal fitting 21 serve as insert articles. When the connector 11—i.e., a part of the resin structure, is formed by injection molding, two main molds (metallic mold) and another metallic mold (slide core or the like) are generally required. The two main molds close the bottom wall 3 of the case main body 2, and the other metallic mold corresponds to the recessed portion 16 of the connector 11 and an undercut portion formed by the inner and outer ends 21a and 21b of the terminal fitting 21. That is, in such a resin formation, when the recessed portion 16 of the connector 11 is formed at the outer side wall 5 of the case 1, the other metal mold (slide core) that perpendicularly slides with respect to the closing direction of the two main molds is necessary. Further, for example, a detachable core (a nested mold) is required for forming the gap G between the projecting portion 21b of the terminal fitting 21, which projects inward of the side wall 5, and the bottom wall 3. That is, such case 1 that is the metal-resin composite body is integrated with the connector 11 through a molding process using the molds shown in FIGS. 10 and 11. The molding process will be described with reference to FIGS. 10 and 11. Notably, the bottom wall 3 of the case 1 is positioned upward in these drawings.
As shown in FIG. 10B, the terminal fitting 21 is disposed on a first mold 101 (lower mold in the drawing) shown in FIG. 10A. Then, as shown in FIG. 10C, a detachable core (core mold) 61 is disposed on a undercut portion corresponding to the gap G formed between the projecting portion 21b of the terminal fitting 21, which projects inward of the case 1, and the bottom wall 3. Thereafter, as shown in FIG. 10D, the case main body 2 that is the metal component is positioned relative to terminal fitting 21. Subsequently, as shown in FIG. 10E, a slide core (core type) 205 used for forming the connector 11 at the outside of the case 1 slides and is disposed on the first mold 101 from the left-hand side in the drawing, and then a second mold 201 (upper mold in the drawing) is taken down from the upper side so as to close the first mold 101 as shown in FIG. 10F. Thereafter, resin is poured (filled) in a cavity (space) K that corresponds to the connector 11 while the mold is closed (refer to FIG. 11G).
In this way, the resin-made connector 11 is integrated with the case main body 2 by injection molding while including the terminal fitting 21 therein. After solidification of the resin, the second mold 201 is released upwards in order to eject the case (molded body) as shown in FIG. 11H. Subsequently, as shown in FIG. 11I, the core 205 is slid toward the left-hand side and removed from the connector 11 (refer to FIG. 11G). Then, as shown in FIG. 11J, the molded case 1 and the core 61 are ejected from the first mold 101. Thereafter, the core 61 is slid out from the molded body 1 as shown in FIG. 11K to thereby complete the case 1 that is the metal-resin composite body.
In a metal-resin composite body, such as the case 1, portions of the connector 11 which correspond to the outside of the case main body 2 and the terminal fittings 21 that are included in the connector 11 serve as undercut portions when the connector 11 that is a resin structure is formed in the case main body 2 by injection molding. Thus, in addition to the first and second molds 101, 201 which close the bottom wall 3 therebetween as shown in FIGS. 10 and 11, the core 205 for forming the recessed portion 16 of the connector 11 and the core 61 corresponding to the gap G between the projecting portion 21b of the terminal fitting 21, which projects inward of the case, and the bottom wall 3 are necessary. Therefore, the configuration of each mold and the process of injection molding become complicated. Although the case main body 2 and the terminal fitting 21 are used as insert articles in the case 1, the same problems still remain when the case main body 2 is used as an only insert article.
That is, when manufacturing the metal-resin composite body having the above configuration, the configuration of the mold and the process of the injection molding become complicated in the case where the connector 11 that is the resin structure is integrated with the case main body 2 that is the metal component by injection molding. As the shape and the configuration of the connector 11 that is the resin structure and those of the case main body 2 that is the metal component are complicated, the structure of the mold and the process of injection molding become complicated. Thus, conventionally, there were roughly four problems on the manufacturing of such metal-resin composite body as indicated below (1)˜(4):
(1) Manufacturing the mold is costly due to a complication of the mold structure, such as a slide core.
(2) The complicated mold leads to a complication of molding process and work, resulting in deterioration in a manufacturing efficiency. Therefore, the cost of the injection molding of the resin structure or the manufacturing cost of the metal-resin composite body rise.
(3) When the structure of the mold becomes complicated, a gap between the molds and/or between the mold and a closing face of a metal component (insert article) is likely to be formed. Thus, a defect, such as a burr (excessive resin), is likely to occur.
(4) Limitations on a shape of resin structure and on its structural design are required due to the reasons stated above (1)˜(4). Therefore, suitable shape and structure of the resin structure may not be materialized. That is, the degree of design freedom of the resin structure is low.
The present invention has been accomplished in order to solve the above problems. An object of the present invention is to provide a technology enhancing a degree of design freedom of a resin structure of a metal-resin composite body, such as a case with a connector used for housing a wiring board in which a resin connector is integrated with a metal case main body, the metal-resin composite body comprised of: the resin structure that includes a conduction path component; and a metal component integrated with the resin structure.